Locking mechanisms

ABSTRACT

A locking mechanism particularly applicable to vehicle antitheft devices comprises two telescopic members one of which has a series of recesses and the other of which has a detent spring urged into engagement with said recesses. The detent is mounted for angular movement into said recesses whereby it locks the two members against relative movement in one direction by a wedging action while permitting movement in the other and means operable for example by a key is provided to release the members for movement in both directions by moving said detent against the spring loading.

Zaidener 1 May 23, 1972 541 LOCKING NECSMS 3,245,239 4/1966 Zaidener..70/202 3 462 982 8/1969 Moore [72] Inventor: Kitty Zaidener, 36,Han'uton Court, Maida 1 vale, London w 9, England 3,504,405 4/1970Ell1ott-Sm1th ..70/1 4 X 22 il O 13 1970 FOREIGN PATENTS OR APPLICATIONS2 1 App]. 30 31 716,436 12/1931 France ..70/34 1,026,347 4/1953 France[30] Foreign Application Priority Data Primary Examiner-Albert G. Craig,Jr.

Apr. 8, 1970 Great Britain ..16,783/70 Attorney-$311011, Nolan Neale,Nies & Km

52 US. Cl ..70/202, 70 14, 70 21 1, ABSTRACT In Cl B 32 32 A lockingmechanism particularly applicable to vehicle anti- 2; i theft devicescomprises two telescopic members one of which o 0 70/19 has a series ofrecesses and the other of which has a detent spring urged intoengagement with said recesses. The detent is mounted for angularmovement into said recesses whereby it [56] References Cited locks thetwo members against relative movement in one UNITED STATES PATENTSdirection by a wedging action while permitting movement in the other andmeans operable for example by a key 15 provided 1,530,177 3/1925 Heyer..70/39 to release the members f movement in h directions by 1,864,8836/1932 Anderson ..70/l4 moving i detem against the swing loading2,140,066 12/1938 White ....70/l4 1,098,103 5/1914 Freschl ..70/19 X 5Claims, 4 Drawing Figures I O I 4 I 5 I I 1/ it ill mg a, 12

PATENTEDMAYZB I912 3.664.164

i FIG 7. 13 23 v 13 'QITTQ INVENTOR KITTY ZAIDENER STRAUCH, NOLAN,NEALE, NIES & KU

LOCKING MECHANISMS BACKGROUND OF THE INVENTION This invention relates tolocking mechanisms which have particular application to vehicleanti-theft devices such as are described in the specifications of myBritish Pats. No. 1,007,711, No. 1,039,980 and No. 1,107,012.

In one form of anti-theft device, telescopic members are locked togetherby a cam-operated ball which, in the unlocked state, allows the movablemember to slide in a series of steps; this form of device involvesseparate actions in looking and unlocking. In another form of anti-theftdevice, a springloaded pawl is provided to give a ratchet effect, butthis involves the disadvantage of requiring the lock to be heldcontinuously in the free position during retraction of the movablemember.

SUMMARY OF THE INVENTION It is an object of the present invention toovercome the above disadvantages by providing a simple and effectivelocking mechanism, primarily intended to be operated by a key, to allowor prevent movement between two telescopic members.

It is a further object of the invention to provide such a lockingmechanism which has a spring-loaded detent on one of said members and aseries of locking recesses on the other which cooperate to provide aratchet effect, and which has a construction such that the recesses maybe in the form of easily machined depressions rather than ratchet teeth.

It is a still further object of the invention to provide such a lockingmechanism with a key-operated means for holding said detent in releasedand locking positions and having stable released and locking positions.

BRIEF DESCRIPTION OF THE DRAWINGS series of recesses on one of themembers of the locking mechanism.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to the drawings, thelocking mechanism is securely mounted at the open end of tubular member1 l of the anti-theft device. As described in my aforementioned patents,the anti-theft device comprises the tubular member 11, a square-sectionrod 12, and hooked parts 13 provided at-the ends of the telescopicmembers 11 and 12.

The square-section rod 12 is formed with a series of conical recesses 14and, in its side, is formed with a notch 15 arranged to be engaged by afinger carried at the end of a leaf spring 16 to prevent accidentalcomplete withdrawal of the rod.

The locking mechanism 10 comprises a casing 17in which a detent 18 ismounted on a pivot 19. The detent is urged towards the rod 12 by acompression spring 20 and an opening is provided in the tubular member11 to allow end 21 of the detent to engage the recesses.

A disc-like cam 22 is mounted within the casing, on a vertical shaft,and can be rotated between two positions by means of a key 23. The camis arranged to engage the body of the detent 18 so that, in the camposition shown in FIG. 3, the detent is moved against spring action outof contact with the recesses 14.

In operation of the device, in the unlocked position (FIG. 2) the rod 12can be moved freely within the tube. 0n the other hand, when the cam 22is turned to allow the detent to engage the recesses 14, the rod may bemoved in the closing direction, i.e. arrow A, during which movement thedetent l8 acts as a spring-loaded pawl to promote movement in a seriesof steps; however, on attempted movement of the rod in the directionopposite to arrow A, the detent enters a recess 14 and locks the rodagainst further movement and attempted forcing of movement in thisdirection forces the detent into more positive engagement with therecess in question.

It will be appreciated that, in its application to an anti-theft deviceof the kind described, the locking mechanism can be opened by simplyturning the key whereupon the device can be removed; the mechanism isheld frictionally in each of its two positions.

On the other hand, the device can be readily applied in its workingposition by turning the key to the "locked position and then moving thetelescopic parts together as far as possible; when the two hooks 13engage the control pedal and the steering wheel of the vehicle, movementof the telescopic parts is stopped, and the parts cannot be moved apartdue to the locking action of the detent.

Whereas prior art devices require sharply angled teeth edges in a rachetand pawl slip lock arrangement, the locking faces or reaction surfacesof each rachet tooth being set at at least a angle with respect todirection of movement of the operative parts of the slip lock, it hasbeen found in the present invention that a gently sloping reactionsurface will still perform the desired function in a slip lock assembly.Thus, it will be noted that the locking recesses 14 may be formed bysimply shallow drilling the face of rod 12 upon which the recesses areto be formed, thereby resulting in a considerable expense saving in thata row of carefully machined rachet teeth are unnecessary. Additionally,unlike prior art devices, no sharp teeth edges are exposed which mightcause injury to the hands of the user of the invention.

Although the locking mechanism is described above with reference toanti-theft devices, it also has other applications in locking togetherother relatively movable mechanical parts.

What is claimed is: I

1. An anti-theft device for a road vehicle having a steering wheel andat least one control pedal, comprising a first elongated part and asecond elongated part telescopically receiving said first elongatedpart, a first shaped member at the outer end of one of said parts forreceiving and holding a part of the steering wheel, a second shapedmember at the outer end of the other of said parts for receiving andholding a part of the control pedal, said first elongated part having aseries of conical recesses spaced therealong in the direction oftelescopic movement, said second elongated part having a detentpivotally mounted thereon on an axis which is perpendicular to thedirection of telescopic movement and spaced from said first elongatedpart, said detent having a working end spaced from said pivotal axis bya distance greater than the distance between said pivotal axis and aplane defined by the bottoms of said conical recesses, each of saidrecesses having a reaction surface arranged to mate with said detentworking end, said reaction surface lying in a plane disposedsubstantially angularly outwardly with respect to a vertical linecoincident with the shortest distance between said pivotal axis and saidfirst elongated part, resilient means biasing said detent intoengagement with said recesses, whereby 'upon telescopic movement of saidfirst and second elongated parts away from each other, said detentworking end and a recess reaction surface are wedged together to preventsuch telescopic movement, and whereby upon 'telescopic movement of saidelongated parts towards each other, said detent working end rides oversaid recesses against the force of said biasing means thereby permittingtelescopic movement of said elongated parts towards each other, and lockcontrolled means for moving said detent against said biasing means tofree said detent from said recesses.

2. An anti-theft device as claimed in claim 1, in which said lockcontrolled means for moving said detent comprise a rotary cam which ismanually operable to hold said detent against the action of saidbiassing means.

mately equal the internal dimensions of said tube.

5. An anti-theft device as claimed in claim 4, wherein said conicalrecesses comprise means defining a plurality of aligned conical recessesformed in one surface of said rod, each having a vertical axis arrangedsubstantially normal to said rod one surface.

1. An anti-theft device for a road vehicle having a steering wheel andat least one control pedal, comprising a first elongated part and asecond elongated part telescopically receiving said first elongatedpart, a first shaped member at the outer end of one of said parts forreceiving and holding a part of the steering wheel, a second shapedmember at the outer end of the other of said parts for receiving andholding a part of the control pedal, said first elongated part having aseries of conical recesses spaced therealong in the direction oftelescopic movement, said second elongated part having a detentpivotally mounted thereon on an axis which is perpendicular to thedirection of telescopic movement and spaced from said first elongatedpart, said detent having a working end spaced from said pivotal axis bya distance greater than the distance between said pivotal axis and aplane defined by the bottoms of said conical recesses, each of saidrecesses having a reaction surface Arranged to mate with said detentworking end, said reaction surface lying in a plane disposedsubstantially angularly outwardly with respect to a vertical linecoincident with the shortest distance between said pivotal axis and saidfirst elongated part, resilient means biasing said detent intoengagement with said recesses, whereby upon telescopic movement of saidfirst and second elongated parts away from each other, said detentworking end and a recess reaction surface are wedged together to preventsuch telescopic movement, and whereby upon telescopic movement of saidelongated parts towards each other, said detent working end rides oversaid recesses against the force of said biasing means thereby permittingtelescopic movement of said elongated parts towards each other, and lockcontrolled means for moving said detent against said biasing means tofree said detent from said recesses.
 2. An anti-theft device as claimedin claim 1, in which said lock controlled means for moving said detentcomprise a rotary cam which is manually operable to hold said detentagainst the action of said biassing means.
 3. An anti-theft device asclaimed in claim 2, wherein said lock controlled means further comprisekey-operated means to actuate said cam.
 4. An anti-theft device asclaimed in claim 1, in which said second elongated part comprises atube, rectangular in cross-section, and said first elongated partcomprises a rod, rectangular in cross-section and having externaldimensions approximately equal the internal dimensions of said tube. 5.An anti-theft device as claimed in claim 4, wherein said conicalrecesses comprise means defining a plurality of aligned conical recessesformed in one surface of said rod, each having a vertical axis arrangedsubstantially normal to said rod one surface.